1. Field of the Invention
This invention concerns a dairy parlor gate particularly useful in connection with electronic animal identification systems. More particularly, the invention concerns a non-magnetically conductive gate with an electrically non-conductive coupler to interrupt the formation of a magnetic loop, and a dairy parlor incorporating the gate, whereby the gate is mounted for swinging movement into and/or through the electromagnetic field of the identification system.
2. Description of the Prior Art
The modern dairy farm increasingly employs highly technical features to maximize animal throughput and milk production. While dairy animals may include goats or other animals, cows are by far the animals most frequently milked in large dairy operations. Many farms can now milk upwards of one hundred cows at a time, with entry to the milking stalls controlled by automated systems. To this end, automatic entry gates are provided for entry of a string of cows into the milking stalls. These stalls may have different arrangements known to those in the industry as parallel, herringbone, etc. The cows enter the milking area and face in a common direction to permit the operator to attach milking equipment to the udders of the cows in sequence. After the milk is extracted, the cows leave the milking stalls in unison and a new string of cows are admitted into the milking stalls.
As dairy farmers seek to achieve greater efficiency, monitoring many facets of the cow including the milk production and feed intake becomes important. A now accepted method of achieving this result is the use of transponders suspended from a strap around the cows neck. For example, U.S. Pat. No. 4,798,175, hereby incorporated by reference, discloses an electronic identification system for identifying an animal moving through a portal structure. The identification system includes a transponder for attaching to a cow and an antenna loop which generates a multi-directional electromagnetic field in a portal structure. The transponder is energized by the electromagnetic field when the cow passes through the portal structure. The energized transponder transmits identifying data to a microprocessor for use in counting and identifying the cow. By reading the transponders of each cow, the number of pounds of milk, measured by weigh meters at each stall, can be monitored and recorded to ensure that feeding and breeding are properly controlled.
One problem which has been prevalent in the use of such electronic identification systems in dairy parlors has involved reading the transponder of the first cow in the string. Typical dairy parlor installations have positioned the gate controlling entry into the milking parlors far enough away from the scanner of the identification system so that the transponder worn by the first cow in the string is not activated by the scanner. This first cow's head is already past the scanner when the gate opens and there is nothing to compel the cow to move back so that the transponder can be read. Thus, the effectiveness of the monitoring system is reduced. The placement of the entry gate on the milking stall side of the scanner rather than ahead of the scanner is preferred by farmers so that the gate can also hold the last cow of the string in position against lateral movement. That is to say, when the gate is in the closed position, the last cow is held between a stanchion and the entry gate to prevent her from moving out of position and the reach of the herdsman.
The stanchions and gates in the dairy parlor must be strong to withstand the stress of controlling cows weighing in excess of half a ton. The most popular dairy cow is the Holstein, which is also typically the largest. Gates and stanchions must also withstand the harsh chemicals used in cleaning and flushing a barn, as well as the urine, manure and other naturally generated but corrosive materials. For these reasons, synthetic resin or aluminum gates and stanchions have been unsatisfactory, with stainless steel and galvanized steel being far and away the preferred and accepted materials for stanchion, stall and gate construction in the parlor.
Unfortunately, stainless and galvanized steel include significant quantities of magnetically conductive materials, which include iron, nickel and cobalt, and thus interfere with the operation of the electronic identification system. When an electrically conductive gate having a magnetically conductive loop passes into and/or through the identification system, the magnetically conductive gate becomes charged by the electromagnetic field. This diminishes the strength of the electromagnetic field and interferes with the normal operation of the animal identification system. More particularly, this interference often results in insufficient electromagnetic coupling between the antenna loop and the transponder attached to the cow.
There has accordingly developed a need for a dairy parlor gate which can be positioned between the identification system and the milking stall, made of stainless steel or galvanized steel, and which can be placed adjacent to the identification system electromagnetic field without interfering with its operation.